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fgdata/Docs/README.sound
2004-08-21 08:57:29 +00:00

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ALSA surround sound (5.1) setup
-------------------------------------
(taken from http://floam.ascorbic.com/how-to/alsa5.1)
Make a ~/.openalrc, we are telling OpenAL that we want surround sound and
we want to use ALSA instead of OSS.
(define speaker-num 4)
(define devices '(alsa))
(define alsa-out-device "surround40:0,0")
ALSA and Arts
-------------------------------------
I'm using kernel 2.6.5 with alsa, my sound module is snd-intel8x0. When I ran
fgfs, I'd get quite 'choppy' sound (wasn't smooth, there'd be a couple of
breaks in the sound every second or so). Running arts, and starting fgfs with
"artsdsp fgfs" (from the artsdsp website: "When an application is run under
artsdsp all accesses to the /dev/dsp audio device are intercepted and mapped
into aRts API calls. While the device emulation is not perfect, most
applications work this way, albeit with some degradation in performance and
latency.") would improve the situation, but it seemed to still be choppy.
This command:
echo "fgfs 0 0 direct" >/proc/asound/card0/pcm0p/oss
(from the alsa kernel OSS emulation website:
"The direct option is used, as mentioned above, to bypass the automatic
conversion and useful for MMAP-applications")
made my sound work beautifully when fgfs was run with artsdsp. Running without
artsdsp however (with artsd suspended or killed), would give me no sound at all
(which I find a bit strange)
The following websites might help people with similar troubles:
http://www.alsa-project.org/~iwai/OSS-Emulation.html
http://www.arts-project.org/doc/handbook/artsdsp.html
Computer info:
kernel 2.6.5
flightgear 0.9.4
simgear 0.3.5
plib 1.8.3
soundcard is onboard an asus p4p800-e deluxe mobo (using snd-intel8x0), alsa, related modules from lsmod:
Module Size Used by
snd_pcm_oss 53252 1
snd_mixer_oss 19968 1 snd_pcm_oss
snd_intel8x0 33476 1
snd_ac97_codec 63492 1 snd_intel8x0
snd_pcm 97408 2 snd_pcm_oss,snd_intel8x0
snd_timer 26112 1 snd_pcm
snd_page_alloc 11396 2 snd_intel8x0,snd_pcm
snd_mpu401_uart 7936 1 snd_intel8x0
snd_rawmidi 24832 1 snd_mpu401_uart
snd_seq_device 8324 1 snd_rawmidi
snd 53892 9 snd_pcm_oss,snd_mixer_oss,snd_intel8x0,snd_ac97_codec,snd_pcm,snd_timer,snd_mpu401_uart,snd_rawmidi,snd_seq_device
soundcore 10208 2 snd